Poly(dimethylsiloxane) (PDMS) films composed of gold nanomaterials have drawn increasing interest for their application in biosensors. However, gold and PDMS exhibit poor compatibility, limiting their sensitivity in biosensing. Herein, we reported a surface stress biosensor based on a gold nanoparticle-PDMS (AuNP-PDMS) composite film to detect bovine serum albumin (BSA). The AuNP-PDMS film was fabricated by in situ reduction of PDMS and further reduction of glucose. The compatibility between gold and PDMS was improved via a two-step reduction of AuNPs. The surface stress biosensor can specifically detect BSA molecules within the 0-50 μg/mL concentration range using the direct assay and the sandwich assay. The sandwich assay amplified the surface stress and reduced the limit of detection to 0.035 μg/mL, which is lower than that achieved by the direct assay. The sandwich-type biosensor also exhibits stability, repeatability, and specificity. This study is expected to drive the development of new methods for biomolecule detection.
Keywords: BSA detection; sandwich assay; self-assembly AuNPs; surface stress biosensor.